use apache commons math
use apache commons math ClassicalRungeKutta as integrator
switch to euler to have at least some kind of data
use apache-commons-math3 3.2
solve ODE for velocity and position with runge-kutta
explicitly separate julian time (days) and si units (seconds) via value classes
correctly respect divisions with units
unittest days
small improvements/fixes for csv output
adjust tolerance
use more realistic values for the probe
sort the systems by date